| 1. |
- Aryal, Nabin, et al.
(författare)
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Microbial electrochemical approaches of carbon dioxide utilization for biogas upgrading
- 2022
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 291:Part 1
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Tidskriftsartikel (refereegranskat)abstract
- Microbial electrochemical approach is an emerging technology for biogas upgrading through carbon dioxide (CO2) reduction and biomethane (or value-added products) production. There are limited literature critically reviewing the latest scientific development on the Bioelectrochemical (BES) based biogas upgrading technology, including CO2 reduction efficiency, methane (CH4) yields, reactor operating conditions, and electrode material tested in BES reactor. This review analyzes the reported performance and identifies the crucial parameters to be considered for future optimization, which is currently missing. In this review, the performances of BES approach of biogas upgrading under various operating settings in particular fed-batch, continuous mode in connection to the microbial dynamics and cathode materials have been thoroughly scrutinized and discussed. Additionally, other versatile application options associated with BES based biogas upgrading, such as resource recovery, are presented. The three-dimensional electrode materials have shown superior performance in supplying the electrons for the reduction of CO2 to CH4. Most of the studies on the biogas upgrading process conclude hydrogen (H2) mediated electron transfer mechanism in BES biogas upgrading.
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| 2. |
- Bajracharya, Suman, et al.
(författare)
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Prime Techniques for Pre- and Post-Treatments of Anaerobic Effluents and Solids
- 2020
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Ingår i: Environmental Microbiology and Biotechnology. - Singapore : Springer Nature. ; , s. 255-289
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Several pre-treatment approaches have been explored to enhance the anaerobic fermentation kinetics and efficiency, which include thermal-alkaline treatment, free ammonia, sequential ultrasound techniques as well as grinding, and sieving. Additionally, valorization of mineralized compounds and production of reusable water can also be achieved via post-treatments. The post-treatment concept allows preserving or recovery of value-added byproducts in the form of manures, soil conditioners, and renewable energy. In this chapter, we explain the recent advancement in the pre-treatment and post-treatment of anaerobic digestate to enhance the anaerobic process and for the removal of undesirable compounds, recovery of energy, nutrients, and waste stabilization before disposal.
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| 3. |
- Elsamadony, Mohamed, et al.
(författare)
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Perspectives on Potential Applications of Nanometal Derivatives in Gaseous Bioenergy Pathways: Mechanisms, Life Cycle, and Toxicity
- 2021
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Ingår i: ACS Sustainable Chemistry and Engineering. - : AMER CHEMICAL SOC. - 2168-0485. ; 9:29, s. 9563-9589
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Tidskriftsartikel (refereegranskat)abstract
- Nanosized metal derivatives (NMDs), referring to metals and their oxides, are extensively utilized as additives for anaerobic digestion (AD) and dark fermentation (DF) processes, for enhancing the production of methane (CH4) and hydrogen (H-2), respectively. NMDs-derived positive impacts were widely confirmed in many previous studies; however, no consensus exists about how these have been acquired. Undoubtedly, NMDs affect extracellular electron transfer (EET). Consequently, we explore how biotic-biotic interactions, referring to direct interspecies electron transfer (DIET) among AD partners, and biotic-abiotic exchanges, which are mediated by redox reactions with metals, are affected. In this perspective, the mechanisms behind all those effects are reviewed and explained in detail, considering the specific properties of each NMD, e.g., size and type. We discuss previous studies that offer contradicting interpretations about which process dominates metal oxidation, metal reduction, or DIET. In addition, the fate of NMDs residues in the digestate after the treatment process is discussed, focusing on NMDs toxicity. From previous literature, the environmental impacts are evaluated for the production process of NMDs that are utilized in AD and DF processes via life-cycle assessment. This review provides a comprehensive understanding of NMDs-microbes interactions, which are mandatory for (i) building clear scientific knowledge about processes in play and (ii) engineering favorable conditions to achieve optimum yields in AD and DF processes.
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| 4. |
- Leipold, Sina, et al.
(författare)
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Lessons, narratives, and research directions for a sustainable circular economy
- 2023
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Ingår i: Journal of Industrial Ecology. - : Wiley. - 1088-1980 .- 1530-9290. ; 27:1, s. 6-18
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Tidskriftsartikel (refereegranskat)abstract
- The current enthusiasm for the circular economy (CE) offers a unique opportunity to advance the impact of research on sustainability transitions. Diverse interpretations of CE by scholars, however, produce partly opposing assessments of its potential benefits, which can hinder progress. Here, we synthesize policy-relevant lessons and research directions for a sustainable CE and identify three narratives—optimist, reformist, and skeptical—that underpin the ambiguity in CE assessments. Based on 54 key CE scholars’ insights, we identify three research needs: the articulation and discussion of ontologically distinct CE narratives; bridging of technical, managerial, socio-economic, environmental, and political CE perspectives; and critical assessment of opportunities and limits of CE science–policy interactions. Our findings offer practical guidance for scholars to engage reflexively with the rapid expansion of CE knowledge, identify and pursue high-impact research directions, and communicate more effectively with practitioners and policymakers.
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| 5. |
- Nizami, Abdul-Sattar, et al.
(författare)
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Waste biorefineries : enabling circular economies in developing countries
- 2017
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Ingår i: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 241, s. 1101-1117
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Tidskriftsartikel (refereegranskat)abstract
- This paper aims to examine the potential of waste biorefineries in developing countries as a solution to current waste disposal problems and as facilities to produce fuels, power, heat, and value-added products. The waste in developing countries represents a significant source of biomass, recycled materials, chemicals, energy, and revenue if wisely managed and used as a potential feedstock in various biorefinery technologies such as fermentation, anaerobic digestion (AD), pyrolysis, incineration, and gasification. However, the selection or integration of biorefinery technologies in any developing country should be based on its waste characterization. Waste biorefineries if developed in developing countries could provide energy generation, land savings, new businesses and consequent job creation, savings of landfills costs, GHG emissions reduction, and savings of natural resources of land, soil, and groundwater. The challenges in route to successful implementation of biorefinery concept in the developing countries are also presented using life cycle assessment (LCA) studies. (C) 2017 Elsevier Ltd. All rights reserved.
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